arXiv subjects

Zhi-Gang Wang

Publications and source records attributed to Zhi-Gang Wang.

At least 37 records · Page 2Linked to original sources

arXiv2026

Two-body strong decays of the pseudoscalar hidden-charm tetraquark states via the QCD sum rules

In this work, we study the properties of the pseudoscalar hidden-charm tetraquark states by analyzing their two-body strong decays via the QCD sum rules based on rigorous quark-hadron duality. We take into account the vacuum condensates up to dimension 5 on the QCD side, and obtain the hadronic coupling constants. At last, we obtain the total decay widths $Γ(Z_{c}^{-}) = 326.20^{+4.26}_{-3.11}$ MeV and $Γ(Z_{c}^{+}) = 91.84^{+0.96}_{-0.76}$ MeV, respectively, where the $Z_{c}^{+}$($J^{PC}=0^{-+}$) and $Z_{c}^{-}$($J^{PC}=0^{--}$) denote the pseudoscalar hidden-charm tetraquarks with the diquark-antidiquark structures $[uc]_{A}[\bar{d}\bar{c}]_{V}-[uc]_{V}[\bar{d}\bar{c}]_{A}$ and $[uc]_{A}[\bar{d}\bar{c}]_{V}+[uc]_{V}[\bar{d}\bar{c}]_{A}$, respectively.

hep-ph↗

arXiv2026

Harmonic K-quasiconformal Koebe functions: construction and application to Pavlovic's problem

We first construct the harmonic K-quasiconformal Koebe functions, filling a long-standing foundational gap in geometric function theory. This construction provides a unified parametric candidate extremal function framework for conformal mappings, quasiconformal mappings, and harmonic mappings, and we formulate related conjectures for the extremal theory of harmonic K-quasiconformal mappings. By combining this construction with Astala and Koskela's Hp-theory for quasiconformal mappings, we establish a sharp result concerning the optimal order of harmonic K-quasiconformal mappings with bounded Schwarzian norm in harmonic Hardy spaces. Motivated by the work of Chuaqui, Hernandez, and Martin [Math. Ann. 367, 1099-1122, 2017], this result gives a partial solution to Pavlovic's 2014 open problem on the embeddings of harmonic quasiconformal mappings into Hardy spaces, and outlines a path toward its complete solution.

math.CV↗

arXiv2026

Systematic analysis of the form factors of $B_{c}$ to $P$-wave charmonia and corresponding weak decays

In this article, the vector, axial vector and tensor form factors of $B_{c}\to χ_{cJ}$ ($J=0,1,2$) and $B_{c}\to h_{c}$ are analyzed within the framework of three-point QCD sum rules. With the calculated vector and axial vector form factors, we directly study the decay widths and branching ratios of semileptonic decays $B_{c}^{-}\to χ_{cJ}l \barν_l, h_{c}l \barν_l$ $(l=e, μ$ and $τ)$ and analyze the nonleptonic decays $B_{c}^{-}\to χ_{cJ}π^{-}, χ_{cJ}K^{-}, χ_{cJ}ρ^{-}, χ_{cJ}K^{*-}$, $B_{c}^{-}\to h_{c}π^{-}, h_{c}K^{-}, h_{c}ρ^{-}, h_{c}K^{*-}$ by using the naive factorization approach (NFA). These results can provide more information to understand the properties of $B_{c}$ meson and $P$-wave charmonia and to study the heavy quark dynamics.

hep-ph↗

arXiv2026

Analysis of the hidden-charm pentaquark candidates in the $J/ψΞ$ mass spectrum via the QCD sum rules

In this work, we construct the color $\bar{\mathbf{3}}\bar{\mathbf{3}}\bar{\mathbf{3}}$ type local five-quark currents with the light quarks $qss$ in the flavor octet, and study the $qssc\bar{c}$ pentaquark states via the QCD sum rules in a comprehensive way, and we emphasize that we achieve two light-flavor octets. We obtain the mass spectrum of the hidden-charm-doubly-strange pentaquark states with the isospin-spin-parity $IJ^{P}=\frac{1}{2}{\frac{1}{2}}^-$, $\frac{1}{2}{\frac{3}{2}}^-$ and $\frac{1}{2}{\frac{5}{2}}^-$, which can be confronted to the experimental data in the future, especially in the process $Ξ_b^- \to P_{css}^-ϕ\to J/ψΞ^- ϕ$. As a byproduct, we observe that the lowest hidden-charm pentaquark states are not of the scalar-diquark-scalar-diquark-antiquark type, it is not suitable to refer to the scalar and axialvector diquarks as the "good" and "bad" diquarks, respectively.

hep-ph↗

arXiv2026

Analysis of the strong decay $X(4140)\rightarrow J/ψϕ$ via the light-cone QCD sum rules

In this article, we take the $X(4140)$ as the axialvector tetraquark state with the symbolic quark structure $[sc]_S[\bar{s}\bar{c}]_A+[sc]_A[\bar{s}\bar{c}]_S$, and calculate the width of the two-body strong decay $X(4140)\rightarrow J/ψϕ$ within the framework of the light-cone sum rules. Different from the traditional light-cone sum rules, at the phenomenological side, we introduce parameters $C$ to eliminate the contaminations from the higher resonances and continuum states, and match the hadron side with the QCD side of the correlation function based on rigorous quark-hadron duality to obtain the stable QCD sum rules. Then we obtain the decay width $Γ(X(4140)\rightarrow J/ψϕ)=145\pm21\, \text{MeV}$, which is reasonable according to the experimental data $162\pm21^{+24}_{-49 } \,\text{MeV}$ from the LHCb collaboration. The numerical result supports the possibility that the $X(4140)$ could be the $[sc]_S[\bar{s}\bar{c}]_A+[sc]_A[\bar{s}\bar{c}]_S$ type axialvector tetraquark state.

hep-ph↗

arXiv2026

Integral mean estimates for $(α,β)$-harmonic functions

We establish sharp $L^p$ integral mean estimates for $(α,β)$-harmonic functions on the unit disk. Explicit bounds for the functions and their partial derivatives are obtained in terms of boundary data, by means of the associated Poisson-type kernel and hypergeometric function representations. As applications, we derive coefficient estimates and Hardy space-type results, extending well-known inequalities for classical harmonic and $α$-harmonic functions to the $(α,β)$-harmonic setting.

math.CV↗

arXiv2026

Systematic analysis of the D-wave charmonium states with the QCD sum rules

We systematically study the 1D charmonium spin-triplet (with the $J^{PC}=1^{--}, 2^{--}, 3^{--}$) and spin-singlet (with the $J^{PC}=2^{-+}$) via the QCD sum rules in comparison with the recent experimental results. The predicted mass $M_{ψ_1}=3.77\pm{0.09}\,\rm {GeV}$ supports identifying the $ψ_1$ as the $ψ(3770)$, the value $M_{ψ_2}=3.82\pm{0.09}\,\rm {GeV}$ is consistent with the reported observation of the $ψ_2(3823)$, the prediction $M_{ψ_3}=3.84\pm{0.08}\,\rm {GeV}$ supports identifying the $ψ_3$ as the $ψ_3(3842)$. Additionally, we estimate the unobserved $η_{c2}$ state lies at $3.83\pm{0.09}\,\rm {GeV}$, and suggest detection prospects in the future. More experimental data will help us to unravel the mass spectrum of the charmonium states near the open-charm thresholds.

hep-ph↗

arXiv2026

Analysis of the semileptonic decays of $Ξ_{cc}$ and $Ω_{cc}$ baryons in QCD sum rules

We firstly carry out a systematic analysis on the spin $\frac{1}{2}^{+}\rightarrow\frac{3}{2}^{+}$ weak transition process in the framework of three-point QCD sum rules, where the initial and final states are doubly and singly charmed baryons. In the phenomenological side, all possible couplings of interpolating current to hadronic states are considered. In doing operator production expansion at QCD side, the contributions of the perturbative part, vacuum condensate terms of $\langle{\bar qq}\rangle$, $\langle g_{s}^{2}GG\rangle$, $\langle \bar q g_{s}σGq\rangle$ and $g_{s}^{2}\langle{\bar qq}\rangle^{2}$ are all considered. After the form factors in space-like region ($Q^2>0$) are obtained, the numerical results are extrapolated into time-like region ($Q^2<0$) by a fitting function. Using the predicted form factors, we finally analyze the semileptonic decays of $Ξ_{cc}^{++}\rightarrow Σ_{c}^{*+}l^{+}ν_{l}$, $Ξ_{cc}^{++}\rightarrow Ξ_{c}^{\prime*+}l^{+}ν_{l}$, $Ω_{cc}^{+}\rightarrowΞ_{c}^{\prime*0}l^{+}ν_{l}$ and $Ω_{cc}^{+}\rightarrow Ω_{c}^{*0}l^{+}ν_{l}$ with $l=e,μ$. The predictions in this work can deepen our understanding of the dynamics in the decay processes of doubly heavy baryons and provide useful information to explore the possibility of new physics in heavy baryonic decay channels.

hep-ph↗

arXiv2026

Characterizations of harmonic quasiregular mappings in function spaces

We study conjugate-type phenomena for complex-valued harmonic quasiregular mappings in the unit disk across three function space families: $Q(n,p,α)$, $F(p,q,s)$, and the non-derivative $M(p,q,s)$. For a harmonic $K$-quasiregular mapping $f=u+iv$, we first show that if the real part $u$ belongs to $Q_h(1,p,α)$ (with $α>-1$ and $α+1<p<α+2$), the imaginary part $v$ lies in the same space with a $K$-dependent quantitative bound. An analogous stability result is established for the harmonic $F$-scale, with sharp $K$-dependence. These results are extended to harmonic $(K, K')$-quasiregular mappings, yielding explicit estimates with an additional inhomogeneous term involving $K'$. Finally, for normalized harmonic quasiconformal mappings, %$f\in\mathcal S_H(K)$, we derive membership criteria in the harmonic $M$- and $F$-scales, and obtain corresponding conclusions for their natural derivatives, with parameter ranges governed by the order $α_K$ of the family of harmonic quasiconformal mappings.

math.CV↗

arXiv2026

Analysis of the hidden-charm pentaquark candidates in the $J/ψΛ$ mass spectrum via the QCD sum rules

In this work, we distinguish the isospin for the first time and study the diquark-diquark-antiquark type $udsc\bar{c}$ pentaquark states with zero isospin via the QCD sum rules systematically. We distinguish contributions of the pentaquark states with negative parity from positive parity unambiguously and obtain clean QCD sum rules for the pentaquark states with negative parity. Then we adopt the modified energy scale formula to choose the optimal energy scales of the QCD spectral densities, and obtain the mass spectrum of the $udsc\bar{c}$ pentaquark states with the quantum numbers $I=0$ and $J^{P}={\frac{1}{2}}^-$, ${\frac{3}{2}}^-$, ${\frac{5}{2}}^-$, which could interpret the $P_{cs}(4338)$ and $P_{cs}(4459)$ in the $J/ψΛ$ mass spectrum naturally.

hep-ph↗

arXiv2026

Analysis of the hidden-charm pentaquark candidates in the $J/ψp$ mass spectrum with QCD sum rules

In this work, we distinguish the isospin unambiguously to construct the diquark-diquark-antiquark type five-quark currents with the isospin $I=\frac{1}{2}$, and study the $uudc\bar{c}$ pentaquark states with the QCD sum rules systematically for the first time. Then we obtain the mass spectrum of the diquark-diquark-antiquark type $uudc\bar{c}$ pentaquark states with the isospin-spin-parity $IJ^P=\frac{1}{2}{\frac{1}{2}}^-$, $\frac{1}{2}{\frac{3}{2}}^-$ and $\frac{1}{2}{\frac{5}{2}}^-$, and make possible assignments of the $P_c(4312)$, $P_c(4337)$, $P_c(4380)$, $P_c(4440)$ and $P_c(4457)$. As a byproduct, we obtain the lowest hidden-charm pentaquark state which lies just above the $\bar{D}Λ_c$ threshold.

hep-ph↗

arXiv2026

On Koebe-type functions for harmonic quasiconformal mappings

This paper studies a class of Koebe-type harmonic quasiconformal functions. It is motivated by the shear construction of Clunie and Sheil-Small [Ann. Acad. Sci. Fenn. Ser. A I Math. 9: 3--25, 1984] and the harmonic quasiconformal Koebe function. Equivalent univalence conditions, pre-Schwarzian and Schwarzian norms, coefficient inequalities, as well as growth and area theorems for this family of functions are established. These findings improve several previously known results.

math.CV↗

arXiv2025

Systematic analysis of the transition form factors of $B_c$ to $D$-wave charmonia and corresponding semileptonic decays

In this article, the vector, axial vector and tensor form factors of $B_c$ to $D$-wave charmonia $ψ_J$ ($J=1,2,3$) and $η_{c2}$ are analyzed within the framework of three-point QCD sum rules. With the estimated vector and axial vector form factors, we study the decay widths and branching ratios of semileptonic decays $B_c\toψ_Jl\bar{ν_l}$ and $B_c\toη_{c2}l\bar{ν_l}$. Our results indicate that the semileptonic decay branching ratios of $B_c$ to $D$-wave charmonia decreases as the total angler momentum of the final state $D$-wave charmonia increases. For decay processes $B_c\to ψ_1l\barν_l$, $B_c\to ψ_2[η_{c2}]l\barν_l$ and $B_c\to ψ_3l\barν_l$, the branching ratios can reach the order $10^{-3}$, $10^{-4}$ and $10^{-5}$, respectively, which can provide a valuable reference for future experimental measurements for $B_c$ meson by LHCb collaboration. Furthermore, these results also can provide useful information to study the properties of $B_c$ meson and $D$-wave charmonia.

hep-ph↗

arXiv2025

Analysis of the semileptonic decays $Λ_b\toΛ_cl\barν_l$ and $Ξ_b\toΞ_cl\barν_l$ in QCD sum rules

In this article, the electroweak transition form factors of $Λ_b\toΛ_c$ and $Ξ_b\toΞ_c$ are analyzed within the framework of three-point QCD sum rules. In phenomenological side, all possible couplings of interpolating current to hadronic states are considered. In QCD side, the perturbative part and the contributions of vacuum condensates up to dimension 8 are also included. With the estimated form factors, we study the decay widths and branching ratios of semileptonic decays $Λ_b\toΛ_cl\barν_l$ and $Ξ_b\toΞ_cl\barν_l$ ($l=e,μ$ and $τ$). Our results for the branching ratios of $Λ_b\toΛ_cl\barν_l$ are comparable with experimental data and the results from other collaborations. In addition, our prediction for the branching ratio of $Ξ_b\toΞ_cl\barν_l$ can provide a valuable reference for future experimental measurements.

hep-ph↗

arXiv2025

Mass spectra of doubly heavy baryons in the relativized quark model with heavy-quark dominance

In the framework of the relativized quark model, the mass spectra of the doubly heavy baryons are rigorously calculated in the three-quark system under the heavy-quark dominance mechanism, by using the Gaussian expansion method and the infinitesimally-shifted Gaussian basis functions. With the obtained mass spectra of all doubly heavy baryon families, the contribution of each Hamiltonian term to the energy levels is analyzed. It is found that the spin splitting is mainly determined by the spin-dependent interactions associated with the light quark. Moreover, it is shown that the spin splitting evolves regularly with the mass of heavy quarks by the evolution of the spectral structure, which is consistent with the heavy quark symmetry. Meanwhile, the orbital excitation is dominated by the $ρ$-mode, which is different from that of the singly heavy baryons. At last, our analysis indicates that the $Ξ_{cc}^{+}(3520)$ state should not exist truly and the $Ξ_{cc}^{++}(3621)$ should be the true ground state with $J^{P}$ = $\frac{1}{2}^{+}$. It is recommended to design the corresponding experiments to search for the $Ξ_{cc}^{*}$ in the energy range from 3694 to 3714 MeV.

hep-ph↗

arXiv2025

Analysis of the strong vertices of hadronic molecules $DK$, $D^K$, $DK^$ and their bottom analogs

In this work, we analyze the strong vertices of hadronic molecules $DK$, $D^*K$, $DK^*$ and their bottom analogs within the framework of three-point QCD sum rules. The coupling between interpolating currents and low spin particles is considered in the phenomenological side, and the vacuum condensates $\left\langle \bar qq \right\rangle ,\left\langle g_s^2GG \right\rangle ,\left\langle \bar qg_sσGq \right\rangle ,\left\langle g_s^3GGG \right\rangle ,{\left\langle \bar qq \right\rangle ^2}$ are included in the QCD side. As an application of strong coupling constants, we also obtain the partial decay widths of these states, where $Γ_{T_{DK}\rightarrow D_sπ}=10.3_{-2.9}^{+3.0}\mathrm{KeV}$, $Γ_{T_{D^*K}\rightarrow D_s^*π}=24.8_{-5.4}^{+5.5}\mathrm{KeV}$, $Γ_{T_{BK}\rightarrow BK}=101_{-21}^{+36}\mathrm{MeV}$ and $Γ_{T_{B^*K}\rightarrow B^*K}=142_{-25}^{+52}\mathrm{MeV}$. It is shown that the results of $Γ_{T_{DK}\rightarrow D_sπ}$ and $Γ_{T_{D^*K}\rightarrow D_s^*π}$ are compatible with the experimental data of $D_{s0}^*(2317)$ and $D_{s1}(2460)$.

hep-ph↗

arXiv2025

Analysis of the strong vertices $Λ_cD^{()}N^(1535)$ and $Λ_bB^{()}N^(1535)$ in QCD sum rules

In this article, we firstly analyze the mass and pole residue of negative parity nucleon $N^*(1535)$ within the two-point QCD sum rules. Basing on these results, we continuously study the strong coupling constants of vertices $Λ_cDN^*$, $Λ_cD^*N^*$, $Λ_bBN^*$ and $Λ_bB^*N^*$ in the framework of three-point QCD sum rules. At hadron side, all possible couplings of interpolating current to hadronic states are considered. At QCD side, the contributions of vacuum condensate terms $\langle\bar{q}q\rangle$, $\langle g_s^2GG\rangle$, $\langle\bar{q} g_sσGq\rangle$, $\langle\bar{q}q\rangle^2$ and $g_s^2\langle\bar{q}q\rangle^2$ are also considered. By setting the four momentum of $D^{(*)}[B^{(*)}]$ mesons off-shell, the strong coupling constants in deep space-like regions ($Q^2=-q^2\ggΛ_{QCD}^2$) are obtained. Then, the momentum dependent coupling constants in space-like regions are fitted into analytical function $G(Q^2)$ and are extrapolated into time-like regions ($Q^2<0$). Finally, the on-shell values of strong coupling constants are obtained by taking $Q^{2}=-m_{D^{(*)}[B^{(*)}]}^2$. The results are $G_{Λ_cDN^*}(Q^2=-m_D^2)=4.06^{+0.96}_{-0.75}$, $f_{Λ_cD^*N^*}(Q^2=-m_{D^*}^2)=3.73^{+0.68}_{-0.16}$, $g_{Λ_cD^*N^*}(Q^2=-m_{D^*}^2)=9.22^{+3.16}_{-0.36}$, $G_{Λ_bBN^*}(Q^2=-m_B^2)=9.11^{+1.54}_{-1.61}$, $f_{Λ_bB^*N^*}(Q^2=-m_{B^*}^2)=8.55^{+2.69}_{-2.21}$ and $g_{Λ_bB^*N^*}(Q^2=-m_{B^*}^2)=-0.25^{+0.16}_{-0.01}$.

hep-ph↗

arXiv2025

Review of the QCD sum rules for exotic states

We review the exotic states, such as the $X$, $Y$, $Z$, $T$ and $P$ states, and present their possible assignments based on the QCD sum rules. We present many predictions which can be confronted to the experimental data in the future to diagnose the exotic states. Furthermore, we also mention other theoretical methods.

hep-ph↗